Technical Field
The present disclosure relates to an injector that injects an injection solution by puncturing a puncture target with a needle.
Related Art
As one type of injectors, prefilled syringes that are provided in a state in which a medication (injection solution) is filled therein in advance are known. Among the prefilled syringes of such a type, prefilled syringes each including a protection device that prevents careless puncturing due to the exposure of a needle before or after the puncturing have been developed.
For example, in JP 2011-513035 W, a configuration has been disclosed in which the whole injector including the needle is covered with an outer housing (outer cylinder: protection device). This injector exposes a needle tip by moving forward the injector with respect to the outer housing based on a predetermined operation in a puncturing process, thereby puncturing a puncture target. After a medicine is injected into the puncture target, the injector automatically retreats with respect to the outer housing so as to be re-housed. As a result, the exposure of the punctured needle is prevented.
Meanwhile, from the viewpoint of handleability (for example, easiness in storage or conveyance, the operability, and the like), it is preferable that the injector is appropriately small. However, for the needle and a filling portion for a medicine, a size corresponding thereto is necessary, and thus, there is a limitation on a decrease in the size. Particularly, as disclosed in JP 2011-513035 W, there is concern that the size of the injector that includes a protection device is large according to the structure thereof.